Conventional mobile communication usually adopts a cellular-network-based communication manner. Specifically, in a cellular network, when a source terminal is to transmit data to a target terminal, the source terminal is to establish a connection with a base station at first, and then the data of the source terminal is sent to the target terminal through the base station.
Long Term Evolution (LTE) Release 12 (R12) introduces a D2D communication technology, also called as a D2D technology. In the D2D communication technology, a terminal may directly communicate with another terminal by virtue of a resource allocated by a base station.
The whole D2D process may substantially be divided into a D2D discovery process and a D2D communication process, wherein, in the D2D discovery process, a D2D terminal may detect a discovery signal broadcast by another D2D terminal, thereby detecting existence of the other D2D terminal in a short-distance range and recognizing identity information of the other D2D terminal. In the D2D communication process, the D2D terminals may perform data exchange in multiple forms of voice communication, multimedia information sharing or the like at a short distance.
LTE R13 introduces a D2D cooperative relay communication technology. By virtue of the D2D cooperative relay communication technology, when a terminal is located in an environment without network coverage or network coverage of the terminal is poorer, the terminal may access a base station (or access a network) by taking another terminal located in the network coverage as an access board. The terminal taken as the access board may be called as a relay terminal or a relay node.
In a future wireless communication system, besides conventional terminals, there may appear more and more terminals of other types, for example, a smart band, a wireless television, smart glasses, a robot and a watch, and the terminals of these special types are lower in cost, may not have a function of directly accessing a base station and usually require relay terminals for accessing the base station. The terminals of these special types may support different bandwidths and transmit power. In addition, in a D2D cooperative relay communication technology, different relay terminals may be in different states. For example, a relay terminal of which electricity amount or load reaches a certain threshold value may not provide access service for a new terminal.
However, in a conventional art, terminals perform D2D discovery and D2D communication according to a unified manner and may not make regulations according to practical conditions of the terminals, so that such a communication manner is not so flexible.